Abstract:

The invention is directed to a switch assembly which can be used in
situation in which the switch accommodates the flow of high voltage
current. An actuator assembly with moveable contacts is moved by a motor
driven armature. The moveable contacts are in electrical engagement with
the stationary contacts when the armature is in the first position, and
the moveable contacts are spaced from the stationary contacts when the
armature is in the second position. By angling the stationary contacts
and moveable contacts, the linear motion of the armature causes the
moveable contacts to move across the surface of the stationary contacts
as the armature approaches the first position. As all of the movements of
the assembly are in a direction parallel to the axis of the armature, the
assembly can be manufactured and operated reliably in a relatively small
space. In addition, the linear movement on the angled contact provides
for a positive electrical connection even in adverse environments.

Claims:

1. A switch assembly comprising:a housing through which stationary
contacts extend;a motor assembly positioned within the housing;an
armature driven by the motor assembly between a first position and a
second position;at least one actuator assembly with moveable contacts,
the at least one actuator assembly moved by the armature such that the
moveable contacts are in electrical engagement with the stationary
contacts when the armature is in the first position, and the moveable
contacts are spaced from the stationary contacts when the armature is in
the second position;wherein the movement of the armature and the movement
of the moveable contacts are in the same linear direction.

2. The switch assembly as recited in claim 1 wherein the at least one
actuator assembly has conductive bridges with moveable contacts provided
at either end thereof.

3. The switch assembly as recited in claim 1 wherein two actuator
assemblies are provided, the actuator assemblies are positioned at
respective opposite ends of the armature.

4. The switch assembly as recited in claim 2 wherein bridge springs are
provided in engagement with the at least one bridge, the bridge springs
apply a force on the at least one bridge when the armature is in the
first position, the force assists in maintaining the moveable contacts in
electrical engagement with the stationary contacts.

5. The switch assembly as recited in claim 1 wherein the armature has a
coupler extending therefrom, an opening is provided in the armature to
receive the coupler therein.

6. The switch assembly as recited in claim 5wherein the coupler is secured
to the armature by crimping.

7. The switch assembly as recited in claim 5 wherein the coupler is
fabricated from a non-magnetic material which is easily molded.

8. The switch assembly as recited in claim 5 wherein the armature is
fabricated from a material which exhibits magnetic properties when
exposed to a magnetic field.

9. The switch assembly as recited in claim 1 wherein the stationary
contacts and moveable contacts are angled with respect to the direction
of motion as the armature is moved between the first position and the
second position, causing the moveable contacts to move across the surface
of the stationary contacts as the armature approaches the first position
thereby providing a wiping action to remove contamination that may be
present on the surfaces of the stationary contacts and moveable contacts.

10. A switch assembly comprising:a housing through which stationary
contacts extend;a motor assembly positioned within the housing;an
armature driven by the motor assembly between a first position and a
second position;at least one actuator assembly with moveable contacts,
the at least one actuator assembly moved by the armature such that the
moveable contacts are in electrical engagement with the stationary
contacts when the armature is in the first position, and the moveable
contacts are spaced from the stationary contacts when the armature is in
the second position;the stationary contacts and moveable contacts being
angled with respect to the direction of motion as the armature is moved
between the first position and the second position, causing the moveable
contacts to move across the surface of the stationary contacts as the
armature approaches the first position thereby providing a wiping action
to remove contamination that may be present on the surfaces of the
stationary contacts and moveable contacts.

11. The switch assembly as recited in claim 10 wherein the at least one
actuator assembly has conductive bridges with moveable contacts provided
at either end thereof.

12. The switch assembly as recited in claim 10 wherein two actuator
assemblies are provided, the actuator assemblies are positioned at
respective opposite ends of the armature.

13. The switch assembly as recited in claim 11 wherein bridge springs are
provided in engagement with the at least one bridge, the bridge springs
apply a force on the at least one bridge when the armature is in the
first position, the force assists in maintaining the moveable contacts in
electrical engagement with the stationary contacts.

14. The switch assembly as recited in claim 10 wherein the armature has a
coupler extending therefrom, an opening is provided in the armature to
receive the coupler therein.

15. The switch assembly as recited in claim 14 wherein the coupler is
secured to the armature by crimping.

16. The switch assembly as recited in claim 14 wherein the coupler is
fabricated from a non-magnetic material which is easily molded.

17. The switch assembly as recited in claim 14 wherein the armature is
fabricated from a material which exhibits magnetic properties when
exposed to a magnetic field.

18. A switch assembly comprising:a housing through which stationary
contacts extend;a motor assembly within the housing;an armature driven by
the motor assembly between a first position and a second position;at
least one actuator assembly with moveable contacts, the at least one
actuator assembly being moved by the armature such that the moveable
contacts are in electrical engagement with the stationary contacts when
the armature is in the first position, and the moveable contacts are
spaced from the stationary contacts when the armature is in the second
position;the armature having a coupler attached thereto, the coupler
being fabricated from a non-magnetic material and the armature being
fabricated from a material which exhibits magnetic properties when
exposed to a magnetic field.

19. The switch assembly as recited in claim 18 wherein an opening is
provided in the armature, the opening receiving the coupler therein.

20. The switch assembly as recited in claim 19 wherein the coupler is
secured to the armature by crimping.

21. The switch assembly as recited in claim 18 wherein the at least one
actuator assembly has conductive bridges with moveable contacts provided
at either end thereof.

22. The switch assembly as recited in claim 18 wherein two actuator
assemblies are provided, the actuator assemblies are positioned at
respective opposite ends of the armature.

23. The switch assembly as recited in claim 21 wherein bridge springs are
provided in engagement with the at least one bridge, the bridge springs
apply a force on the at least one bridge when the armature is in the
first position, the force assists in maintaining the moveable contacts in
electrical engagement with the stationary contacts.

24. The switch assembly as recited in claim 18 wherein the stationary
contacts and moveable contacts are angled with respect to the direction
of motion as the armature is moved between the first position and the
second position, causing the moveable contacts to move across the surface
of the stationary contacts as the armature approaches the first position
thereby providing a wiping action to remove contamination that may be
present on the surfaces of the stationary contacts and moveable contacts.

Description:

FIELD OF THE INVENTION

[0001]The present invention is directed to electromagnetic switches and to
contact systems related thereto and, in particular, to electromagnetic
switches which can operate under high current conditions.

BACKGROUND OF THE INVENTION

[0002]Electromagnetic switches and relays known in the art typically
consist of a multi-turn coil wound on an iron core forming an
electromagnet. The coil electromagnet is energized by passing current
through the multi-turn coil to magnetize the core. The magnetized coil
attracts an armature to a first position, which is pivoted to connect or
disconnect one or more sets of contacts. When no current is passed
through the coil or the polarization of the current is reversed, the coil
is moved to a second position in which the contacts are disconnected or
connected respectively.

[0003]While these switching devices operate satisfactorily in normal
applications, it has been found that under extremely high current
conditions, e.g. short-circuit conditions, a repulsion force is generated
which tends to part the pairs of contacts, which may cause serious damage
to the switching device.

[0004]U.S. Pat. No. 5,694,099 discloses a switching device which can
operate under high current conditions. The switching device has a
solenoid actuator with a plunger and a pivot arm. The pivot arm has one
end coupled to an outer end of the plunger and the other end bridging and
engaging a moving switch blade of the switching assembly. Within the
bridging member of the pivot arm, a compression spring is seated to
engage the moving blade and provide a further positive pressure to hold
the moving contact in engagement with the fixed contact when the pivot
arm is in the position to cause the fixed and moving contacts to engage.
When the switch is in the "made" condition, the flow of the same current
in opposite directions in the parallel paths, which respectively comprise
the inlet bus-bar and the moving switch blade, generates an
electrodynamic force between them, tending to move the switch blade away
from the fixed inlet bus-bar thereby increasing the force applied to the
moving contact, and thus resisting any tendency of the contacts to
separate under conditions of high current.

[0005]High current switch devices, such as those described above, provide
adequate switching. However, these devices, and in particular the
pivoting arms, tend to be relatively complicated, which increases the
cost and increases the overall size of the switching device. It would,
therefore, be beneficial to provide a switching device which could be
used in high current environments, but which wall easy and inexpensive to
manufacture and which could operate effectively in a reduced space.

SUMMARY OF THE INVENTION

[0006]The invention is directed to a switch assembly which can be used in
a situation in which the switch accommodates the flow of high voltage
current. The switch assembly has a housing through which stationary
contacts extend. The stationary contacts are configured to accept high
voltage current thereon. A motor assembly is provided to drive an
armature between a first position and a second position. An actuator
assembly with moveable contacts is moved by the armature such that the
moveable contacts are in electrical engagement with the stationary
contacts when the armature is in the first position, and the moveable
contacts are spaced from the stationary contacts when the armature is in
the second position.

[0007]The invention is also directed to a switch assembly in which
stationary contacts and moveable contacts may be angled with respect to
the direction of motion as the armature is moved between the first
position and the second position. By angling the contacts and terminals,
the linear motion of the armature causes the moveable contacts to move
across the surface of the stationary contacts as the armature approaches
the first position. This provides a wiping action to remove contamination
that may be present on the surfaces of the stationary contacts and
moveable contacts. The angling also provides an increase in the contact
force for a given spring force.

[0008]The invention is also directed to a switch assembly that is
magnetically latching. The device will utilize an AC signal to actuate by
a pulse of the positive or negative cycle of the signal. The device could
also be configured to utilize a DC signal. The coil only needs to be
energized for a short duration to close the switch and again to open. The
invention is also directed to a switch assembly in which the armature has
a coupler attached thereto. The coupler is fabricated from a non-magnetic
material and the armature is fabricated from a material which exhibits
magnetic properties when exposed to a magnetic field.

[0009]The invention provides a low cost high voltage switch assembly which
can be easily produced. As all of the movements of the assembly are in a
direction parallel to the axis of the armature, the assembly can be
manufactured and operated reliably in a relatively small space. In
addition, the linear movement on the angled contact provides for a
positive electrical connection even in adverse environments.

[0010]Other features and advantages of the present invention will be
apparent from the following more detailed description of the preferred
embodiment, taken in conjunction with the accompanying drawings which
illustrate, by way of example, the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011]FIG. 1 is a top perspective view of a fully assembled switch
according to the present invention.

[0012]FIG. 2 is a top perspective view of the switch, similar to that of
FIG. 1 with a cover removed to show the components housed in the switch
housing.

[0013]FIG. 3 is a perspective view of the coil assembly, with the magnets
exploded therefrom.

[0021]Motor assembly 207 includes coil connections that physically contact
and electrically communicate with the coil terminals 105. Although, as
shown, the motor assembly is configured to receive an alternating current
(AC), the motor assembly 207 may be configured to utilize a direct
current (DC) signal. In addition, motor assembly 207 may be detachably
connected to actuator assemblies 206 by armature 211 (best shown in FIG.
6). The armature 211 is reciprocably driven along an axis 213 to provide
a corresponding reciprocating motion of the attached actuator assemblies
206. The actuator assemblies 206 are driven to a position between a first
position that provides physical contact between moveable contacts 209 and
stationary contacts 203 and a second position that does not provide
contact between moveable contacts 209 and stationary contacts 203. The
arrangement shown in FIG. 2 is a normally open circuit. However, the
invention is not limited to the arrangement shown and may also include
actuator assemblies 206 configured for normally closed circuits or
combinations of normally open and normally closed circuits.

[0022]Referring to FIGS. 2, 7A and 7B, the actuator assemblies 206 include
a plurality of bridges 215. Bridges 215 are fabricated from an
electrically conductive material and are configured to receive and
electrically communicate with moveable contacts 209. Suitable conductive
materials include, but are not limited to, copper, copper alloy, bronze,
brass, silver plating, gold plating or any other conductive material. The
bridges 215 permit electrical connection between corresponding stationary
contacts 203 when the actuator assemblies 206 are driven to a position
that provides physical contact between moveable contacts 209 and
stationary contacts 203. The actuator assemblies 206 further include
bridge springs 217, which apply a force on the bridge 215, urging the
bridge 215 and moveable contacts 209 in a direction toward the stationary
contacts 203, which assists in maintaining physical contact between
moveable contacts 209 and stationary contacts 203 and provides for
reliable, reproducible electrical communication therebetween. The use of
springs 217 can be particularly advantageous when the switch terminals
103 carry high current, as the repulsive force increases between
contacts. The force supplied by the springs 217, in conjunction with the
entire configuration of the switch assembly 100 minimizes the risk that
the stationary contacts 203 and the moveable contacts 209 will be forced
apart under extreme loads such as short circuit conditions. Armature
engagements slots 216 are provided on bridges 215, the slots 216 being
dimensioned to receive a portion of the armature 211 therein.

[0023]Referring to FIG. 2, base housing 101 may also be configured so that
one or more switch terminals 103 are reversed such that stationary
contacts 203 are located such that the stationary contacts 203 are
intermediate to the motor assembly 207 and the actuator assemblies 206.
Combinations of the positioning of the stationary contacts and the
operation of the motor assembly 207 permit the actuator assemblies 206 to
be configured for both normally open and normally closed circuits.

[0024]Motor assembly 207, as shown in FIGS. 3, 4 and 5, includes a coil
assembly 205, which is configured as an electromagnetic arrangement
preferably including a plurality of wire windings. For example, copper
wire may be wound around a bobbin 310 to form coil assembly 205. The wire
on coil assembly 205 is in electrical communication with coil terminals
105 and provides the coil assembly 205 with power to energize the
electromagnetic coil assembly 205. A printed circuit board may be in
electrical communication with components, such as diodes, to provide the
desired current (i.e., convert AC current to DC current) to the coil
assembly 205. As best shown in FIGS. 5 and 6, the coil assembly 205 is
disposed within a solenoid frame 305. Solenoid frame 305 surrounds the
coil assembly 205.

[0025]Coil assembly 205 is disposed about axis 213. In addition, armature
211 is disposed along axis 213, wherein at least a portion of the
armature 211 is disposed within coil assembly 205. The armature 211, as
shown in FIG. 6, has a cylindrical configuration with an actuator
engagement projection 222 extending from one end thereof. The opposite
end is hollowed out to form a coupler receiving opening 223. A coupler
221 is also cylindrical in configuration and is dimensioned to be
received in the coupler receiving opening 223. An actuator engagement
projection 225, similar to projection 222, extends from the end of the
coupler 221 which is not positioned in opening 223. Coupler 221 is
secured to armature 211 by crimping or other known means. For example, a
projection could be provided on either the coupler or the armature which
would snap into a respective recess on the other when the coupler and
armature are fully mated. In the embodiment shown, coupler is made of
plastic or other material which is easy to mold and/or form. The armature
211 is fabricated from a material that exhibits magnetic properties when
exposed to a magnetic field. Suitable materials for the armature 211
include iron or iron alloys, preferably soft magnetic ferritic materials,
that exhibit electromagnetic properties when exposed to a magnetic field.

[0026]A pole piece 231 is provided at the end of coil assembly 205. The
pole piece 231 is housed within the motor assembly 207 and is fabricated
from a material that exhibits magnetic properties. Suitable magnetic
materials are any magnetic material including, but not limited to soft
magnetic ferritic materials. The pole piece 231 is provided proximate the
armature 211. Translation of the armature 211 from a first position in
which the stationary contacts 203 and moveable contacts 209 are not
engaged to a second position in which the stationary contacts 203 and
moveable contacts 209 are engaged is by engerization of the coil assembly
205 by a current pulse or appropriate magnitude and polarity. Once the
armature is seated to the pole piece, the permanent magnets hold the
armature to the pole piece in the first position when the signal is
removed from the coil. A second pulse by the opposite cycle of the signal
is applied to the coil, thus causing the armature to move to the second
position. A spring (not shown) is utilized to keep the armature in the
second position once the signal is removed from the coil.

[0027]In the alternative, a closed magnetic loop may be provided allowing
the permanent magnets 309 to maintain the armature 211 in both the first
and second positions, thereby eliminating the need for the spring. The
coil assembly 205 may either be single wound and fed with pulses of
opposite polarities to effect movement in opposite directions, or double
wound, enabling a pulse of the same polarity to be used to produce motion
of the armature 211 is either direction when applied to the appropriate
one of the two windings. In either case, pole piece 231 (FIG. 5)
cooperates with armature to maintain the armature in position relative to
the coil assembly 205 and prevent excess movement thereof.

[0028]When assembled, as shown in FIGS. 2 and 6, actuator engagement
projections 222, 225 are positioned in respective armature engagement
slots 216 of actuator assemblies 206. Consequently, as the armature 211
is moved to the first position, the actuator assemblies 206 are moved in
the direction indicated by arrow Xo of FIG. 6. In this position, the
moveable contacts 209 are physically and electrically disengaged from
stationary contacts 203, thereby preventing the electrical current from
being conducted across the bridges 215 of the actuator assemblies 206. In
contrast, as the armature 211 is moved to the second position, the
actuator assemblies 206 are moved in the direction indicated by arrow Xc
of FIG. 6. In this position, the moveable contacts 209 are physically and
electrically engaged with stationary contacts 203, thereby providing an
electrically conductive path between a first switch terminal 103, a first
stationary contact 203, a first moveable contact 209, the bridge 215, a
second moveable contact 209, a second stationary contact 203 and a second
switch terminal 103.

[0029]In the embodiment shown in FIGS. 2, 6, 7A and 7B, a portion of each
respective switch terminal 103 and its respective contact terminal 203
are angled with respect to axis 213. Similarly, a respective portion of
the bridge 215 and its respective moveable contacts 209 are angled to be
positioned in a plane which is essentially parallel to the plane of the
respective angled portion of the switch terminal. Consequently, as each
moveable contact 209 is moved into engagement with its respective
stationary contact 203, the surface of the moveable contact 209 will move
across the surface of its respective stationary contact 203, causing the
surface to frictionally engage as the movement occurs, resulting in a
wiping action. This allows for a more reliable electrical connector, as
any contamination will be removed from the surfaces, providing less
resistance between the stationary contact and the moveable contact. This
is particularly beneficial in no load or low load applications. The
degree of angling can be adjusted to provide more or less wiping action,
depending upon the circumstances. By angling the contacts and terminals
in this fashion, the holding force provided in a direction parallel to
the axis 213 may be lessened, but the contact force between the contacts
is enhanced.

[0030]The switch assembly according to the present invention provides a
low cost high voltage switch assembly which can be easily produced. As
all of the movements of the assembly are in a direction parallel to the
axis 213, the assembly can be manufactured and operated reliably in a
relatively small space. In addition, the linear movement on the angled
contact provides for a positive electrical connection even in adverse
environments.

[0031]While the invention has been described with reference to a preferred
embodiment, it will be understood by those skilled in the art that
various changes may be made and equivalents may be substituted for
elements thereof without departing from the scope of the invention. In
addition, many modifications may be made to adapt a particular situation
or material to the teachings of the invention without departing from the
essential scope thereof. Therefore, it is intended that the invention not
be limited to the particular embodiment disclosed as the best mode
contemplated for carrying out this invention, but that the invention will
include all embodiments falling within the scope of the appended claims.